Janus单层MoSSe中的声子传输：第一性原理研究<a href="#fn1" title="PACS编号：72.15.Jf，71.20.-b，71.70.Ej，79.10.-n。">†</a>,Physical Chemistry Chemical Physics

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Janus单层MoSSe中的声子传输：第一性原理研究 †
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2018-02-15 00:00:00 , DOI: 10.1039/c8cp00350e
San-Dong Guo _{1,

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Affiliation

过渡金属双硫属化物（TMD）单层由于其独特的物理性能而得到了广泛的研究。最近，通过用Se原子取代MoS _2中的顶部S原子层，合成了具有夹层S-Mo-Se结构的Janus TMD单层MoSSe 。在这项工作中，我们系统地研究了声子传输和晶格热导率（κ_大号利用第一性原理计算在莫斯单层）与单模弛豫时间近似（RTA）内的线性声子玻耳兹曼方程。所计算出的结果表明，该κ_大号莫斯单层得多比的MoS的降低_2个单层，和比摩西的较高₂单层。在室温下，MoSSe单层的相应导热片电导为342.50 WK ^-1。通过研究声子群的速度和寿命可以理解这一点。相比的MoS _2米的单层，更小的群速度和莫斯单层的更短的声子的寿命产生较低的κ_大号。相比，这些摩西的莫斯的较大群速度₂单层是对于较高的主要原因κ_大号。硫化钼的弹性性质₂，莫斯和摩西_2个单层还计算，和杨氏模量的数量级是相同的，所述的κ_大号。所计算出的结果表明，同位素散射通向的减少5.8％κ_大号。上的尺寸效应κ_大号也被认为是，一般可在设备实现中使用。当莫斯单层的特征长度为约110nm，所述κ_大号减少到一半。这些结果可能为MoSSe单层的热管理提供前景，以用于热电，热电路和纳米电子学中，并可能激发进一步的理论或实验努力来研究Janus TMD单层的热传输。

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Phonon transport in Janus monolayer MoSSe: a first-principles study†

Transition Metal Dichalcogenide (TMD) monolayers are very widely studied due to their unique physical properties. Recently, Janus TMD monolayer MoSSe, with a sandwiched S–Mo–Se structure, has been synthesized by replacing the top S atomic layer in MoS₂ with Se atoms. In this work, we systematically investigate the phonon transport and lattice thermal conductivity (κ_L) in MoSSe monolayers using first-principles calculations and the linearized phonon Boltzmann equation within the single-mode relaxation time approximation (RTA). The calculated results show that the κ_L of MoSSe monolayers is much lower than that of MoS₂ monolayers, and higher than that of MoSe₂ monolayers. The corresponding thermal sheet conductance of MoSSe monolayers is 342.50 W K⁻¹ at room temperature. This can be understood by studying the phonon group velocities and lifetimes. Compared to MoS₂ monolayers, the smaller group velocities and shorter phonon lifetimes of MoSSe monolayers give rise to a lower κ_L. The larger group velocities of MoSSe compared to those of MoSe₂ monolayers are the main reason for the higher κ_L. The elastic properties of MoS₂, MoSSe and MoSe₂ monolayers are also calculated, and the order of the Young's modulus is identical to that of the κ_L. The calculated results show that isotope scattering leads to a 5.8% reduction of the κ_L. The size effects on the κ_L are also considered, and are usually used in device implementation. When the characteristic length of the MoSSe monolayer is about 110 nm, the κ_L reduces to half. These results may offer perspectives on thermal management of MoSSe monolayers, for applications in thermoelectrics, thermal circuits and nanoelectronics, and may motivate further theoretical or experimental efforts to investigate thermal transport in Janus TMD monolayers.

更新日期：2018-02-15

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